Measuring Blood Urea Nitrogen Research Articles

Reference Interval Creation for Symmetric Dimethylarginine (SDMA) in Healthy Hispaniolan Amazon Parrots (Amazona ventralis) and Quaker Parrots (Myiopsitta monachus).

Renal disease is often identified as a cause of morbidity and mortality in avian patients. However, currently, early antemortem detection of renal disease in avian patients is difficult. Anatomical and physiological differences between mammals and birds mean the use of commonly employed diagnostic testing (ie, measurement of blood urea nitrogen [BUN] and serum creatinine, urinalysis, and ultrasonography) are either nondiagnostic or difficult to achieve. Symmetric dimethylarginine (SDMA) is considered a more sensitive marker for renal disease in humans, dogs, and cats. However, SDMA has not yet been assessed for diagnostic use in any psittacine species. In this study, we establish reference ranges for SDMA in both Hispaniolan Amazon parrots (Amazona ventralis, HAP) and Quaker parrots (Myiopsitta monachus, QP). Blood was collected from 23 Amazon parrots and 32 Quaker parrots maintained in research facilities. Measurement of SDMA through a commercially available immunoassay (IA-SDMA) as well as creatinine, BUN, uric acid, phosphorus, calcium, sodium, potassium, and chloride were determined through IDEXX Laboratories. Plasma SDMA concentrations ranged from 6 to 15 µg/dL and 3 to 15 µg/dL for the HAP and QP, respectively. Sex was a confounding factor for the QP population, but sex did not have a significant effect on SDMA for the HAP population. No significant correlations were identified between SDMA concentrations and other parameters in either psittacine species. Our results show proof of concept for the IA-SDMA and provide reference intervals for SDMA in HAP and QP. Further investigation is required to determine the validity of this assay and the predictive power of SDMA in the detection of renal impairment for parrots and other common companion birds.

#598 Successful application of allo-hemodialysis in a porcine model of embolization-induced acute kidney injury

Abstract Background and Aims Annually, millions of kidney patients, primarily in low- and low-middle income nations, die prematurely due to the lack of affordable kidney replacement therapy. We propose a novel, low-cost alternative dialysis modality called allo-hemodialysis (alloHD), where blood of a patient with kidney failure flows counter-current to the blood of a healthy subject (“buddy”) through the dialyzer [1]. Uremic solutes and excess fluid are then excreted by the buddy's healthy kidneys. We have already demonstrated the technical feasibility of alloHD in pigs with acute kidney injury (AKI) induced by renal artery ligation [2]. In this study, we explored alloHD in a less invasive porcine model of AKI induced by renal artery embolization. Method The protocol was approved by the Committee for the Purpose of Control and Supervision of Experiments on Animals (CPCSEA), New Delhi, India. We studied two female Yorkshire pigs (weight 80-90 kg) with central venous catheter as vascular access. AKI was induced by embolization of both kidneys by transcatheter deployment of Contour™ Poly Vinyl Alcohol particles (Boston Scientific, Marlborough, MA, USA). The AKI pig and the buddy pig were connected to the dialysate and blood compartments, respectively, of a Nipro Cellentia 17H dialyzer. The AKI pig was then dialyzed for 4 hours against the healthy buddy pig. During alloHD, both pigs were anticoagulated with heparin (5,000 IU/h) and the buddy pig was sedated with 1-2% isoflurane gas. Blood samples were collected before, during, and after alloHD for measurements of blood urea nitrogen (BUN) and creatinine. Results We performed nine alternate day alloHD sessions with the same pair of pigs. During alloHD, BUN and Creatinine levels declined in the AKI pig (Fig. 1) and increased—as expected—transiently above baseline in the buddy pig and then trended towards baseline post-dialysis (Fig. 1). We found no indication of hemolysis or coagulation of the extracorporeal circuit in any of the nine alloHD sessions. The animals were sacrificed after the 9th session. Conclusion We demonstrated the feasibility of alloHD in a porcine embolization AKI model. This study corroborates and complements our previous experience with alloHD in a porcine model of AKI induced by renal artery ligation. Given these promising results, we are investigating the potential for advancing to a clinical trial.

Hyperoxia Increases Kidney Injury During Renal Ischemia and Reperfusion in Mice.

Renal ischemia and reperfusion (IR) contribute to perioperative acute kidney injury, and oxygen is a key regulator of this process. We hypothesized that oxygen administration during surgery and renal IR would impact postoperative kidney function and injury in mice. Mice were anesthetized, intubated, and mechanically ventilated with a fraction of inspired oxygen (F io2 ) 0.10 (hypoxia), 0.21 (normoxia), 0.60 (moderate hyperoxia), or 1.00 (severe hyperoxia) during 67 minutes of renal IR or sham IR surgery. Additional mice were treated before IR or sham IR surgery with 50 mg/kg tempol, a superoxide scavenger. At 24 hours, mice were sacrificed, and blood and kidney collected. We assessed and compared kidney function and injury across groups by measuring blood urea nitrogen (BUN, primary end point), renal histological injury, renal expression of neutrophil gelatinase-associated lipocalin (NGAL), and renal heme oxygenase 1 ( Ho-1 ), peroxisome proliferator-activated receptor gamma coactivator 1-α ( Pgc1-α ), and glutathione peroxidase 4 ( Gpx-4 ) transcripts, to explore potential mechanisms of any effect of oxygen. Hyperoxia and hypoxia during renal IR surgery decreased renal function and increased kidney injury compared to normoxia. Baseline median (interquartile range) BUN was 22.2 mg/dL (18.4-26.0), and 24 hours after IR surgery, BUN was 17.5 mg/dL (95% confidence interval [CI], 1.3-38.4; P = .034) higher in moderate hyperoxia-treated animals, 51.8 mg/dL (95% CI, 24.9-74.8; P < .001) higher in severe hyperoxia-treated animals, and 64.9 mg/dL (95% CI, 41.2-80.3; P < .001) higher in hypoxia-treated animals compared to animals treated with normoxia ( P < .001, overall effect of hyperoxia). Hyperoxia-induced injury, but not hypoxia-induced injury, was attenuated by pretreatment with tempol. Histological injury scores, renal NGAL staining, and renal transcription of Ho-1 and suppression of Pgc1- α followed the same pattern as BUN, in relation to the effects of oxygen treatment. In this controlled preclinical study of oxygen treatment during renal IR surgery, hyperoxia and hypoxia impaired renal function, increased renal injury, and impacted expression of genes that affect mitochondrial biogenesis and antioxidant response. These results might have implications for patients during surgery when high concentrations of oxygen are frequently administered, especially in cases involving renal IR.

A-357 Performance of Blood Urea Nitrogen on the epoc Analyzer

Abstract Background The epoc Blood Analysis System (Siemens, Tarrytown, NY) performs blood gases, electrolytes, and metabolites using a Blood Gas Electrolyte and Metabolite (BGEM) Test Card panel on 92 uL of whole blood. The BGEM Test Card uses potentiometric sensors to measure sodium, potassium, chloride, ionized calcium, pH, pCO2; amperometric sensors to measure pO2, glucose, creatinine, and lactate; and a conductometric sensor to measure hematocrit. Results are available in 3–10 minutes, depending upon the time of sample injection. TJUH implemented the epoc in its ICUs in 2012 to provide rapid, whole blood Point of Care (POC) results, then expanded to other locations (Emergency Department, Outpatient Radiology, Cardiothoracic Surgery). Siemens recently added a potentiometric sensor for measurement of Blood Urea Nitrogen (BUN) to its BGEM card. We evaluated this card for possible future use. Methods Precision and method comparison studies were performed at our Center City location. Inter- and intra-precision studies were performed on two levels of controls (Eurotrol, Elizabethtown, KY). Remnant whole blood was collected from 30 patients. Comparison studies were performed on the Piccolo Xpress (Abbott, Princeton, NJ), which provides a whole blood BUN measurement using a coupled-enzyme reaction. Results Intra-assay precision for epoc BUN (n = 20, 2 devices) was 2.8%CV and 6.5%CV for Levels 1 and 3, respectively. Inter-assay precision for epoc BUN (n = 20, 2 devices over 10 days) was 2.4%CV and 7.1%CV for Levels 1 and 3, respectively. Method comparison for BUN (n = 30) was: mean = 42, median = 29, r2 = 0.9889, y = 0.8840x-3.6416. Conclusion The epoc BUN studies showed comparable results when compared to the Piccolo Xpress. Previous studies showed good correlation between whole blood on the Piccolo Xpress and plasma on the Roche Cobas c702 which is also a coupled-enzyme reaction; therefore the test is considered acceptable for implementation at our Center City sites where epoc is currently in use.

The protective role of Achyranthes aspera extract against cisplatin-induced nephrotoxicity by alleviating oxidative stress, inflammation, and PANoptosis

Ethnopharmacological relevanceAchyranthes aspera, a widely recognized medicinal plant, is used in various cultures for treating different ailments, including renal dysfunction; however, there is a lack of comprehensive understanding of its protective effects and the underlying signaling networks involved. Aim of the studyThis study aimed to investigate the molecular mechanisms of the action of A. aspera by employing an integrative approach including functional and tissue imaging as well as comprehensive genomics analysis. Materials and methodsCisplatin-induced nephrotoxicity is a well-established animal model for acute kidney injury (AKI). In this study, we investigated the protective effects and underlying mechanisms of the action of A. aspera water-soluble extract (AAW) on a murine model of cisplatin-induced AKI. The evaluation includes measurements of blood urea nitrogen (BUN) and serum creatinine (SCr) levels, histology examination, and transcriptome analysis using RNA sequencing. ResultsIn male ICR mice, oral administration of AAW at doses of 0.5–1.0 g/kg significantly reduced cisplatin-induced nephrotoxicity. This effect included the amelioration of tubular injury, renal fibrosis, and the lowering of BUN and SCr levels. AAW also effectively decreased oxidative markers, such as malondialdehyde (MDA) and nitrotyrosine (NT), along with inflammation markers, including COX-2, iNOS, NLRP3, and pP65NFκB. Moreover, AAW administration induced a dose-dependent increase in the expression of two protective factors, Nrf2 and BcL2, and suppressed apoptosis, as evidenced by reduced levels of truncated caspase 3 (t-Casp3). To explore the underlying molecular mechanisms and signaling networks, next-generation sequencing (NGS) analysis was employed. The results revealed that AAW mitigated apoptosis, necroptosis, and PANoptosis pathways by inhibiting inflammation signaling pathways, such as the TNFα-, NFκB-, NETs-, and leukocyte transendothelial migration pathways. Additionally, AAW was found to enhance protective signaling pathways, including the cGMP/PKG-, cAMP-, AMPK-, and mTOR-dependent activation of autophagy and mitophagy pathways. The primary bioactive compound found in AAW was identified as 20-hydroxyecdysone (0.36%). ConclusionOur study demonstrates that AAW reduces cisplatin-induced nephrotoxicity. The protective effects of AAW are attributed to its modulation of multiple molecular signaling networks. Specifically, AAW downregulates genes and signaling pathways associated with oxidative stress and endoplasmic reticulum (ER) stress, inflammation, and PANoptosis. Simultaneously, it upregulates genes and signaling pathways associated with cell survival, including autophagy and mitophagy pathways.

The effect of tannic acid on renal renin-angiotensin signaling pathway in a model of unilateral ureteral obstruction in male Wistar rats.

The purpose of current study was to elucidate polyphenol tannic acid effect on renal function and activity of the renin-angiotensin system after unilateral ureteral obstruction (UUO). Male Wistar rats were divided into three groups of six randomly: 1) Sham, 2) UUO, and 3) UUO + Tannic acid. Rats in the UUO and UUO + Tannic acid groups experienced unilateral ureteral obstruction. In the Sham group, the abdominal cavity was exposed without UUO induction. In the UUO + Tannic acid group, animals received tannic acid (20mg/kg) intraperitoneally, 6 and 12h after clamping the left ureter and 6 and 12h after the right nephrectomy. Blood samples were taken to measure blood urea nitrogen (BUN) and creatinine levels. Kidney tissue samples were obtained for assessment of oxidative stress, inflammatory indices and the levels of renin-angiotensin system components. Tannic acid administration significantly improved UUO-induced kidney dysfunction (serum BUN: 66.42 ± 14.414mg/dl, p < 0.05; serum creatinine: 1.67 ± 0.258mg/dl, p < 0.05), oxidative stress (MDA level: 95.29 ± 37.35µmol/g tissue, p < 0.05; SOD activity: 59.82 ± 13.41 U/g protein, p < 0.01) and inflammation (renal TNF-α: 57.05 ± 15.653pg/g tissue, p < 0.05; renal IL-6: 117.015 ± 24.076pg/g tissue, p < 0.001). The treatment caused a reduction in the amount of renal angiotensinogen, renin and ACE genes expression compared to the UUO group (Angiotensinogen: 8.9 ± onefold, p < 0.05, Renin: 6.5 ± 1.14 fold, p < 0.05, ACE: 4.9 ± 0.64 fold, p < 0.05). Angiotensin II type 1 receptor protein levels decreased in the tannic acid-treated rats in comparison with the UUO group (0.61 ± 0.136, p < 0.05). According to the result of the current study, tannic acid considerably attenuated the complications of unilateral ureteral obstruction through renin-angiotensin system modulation. Trial registration: IR.TUMS.MEDICINE.REC.1400.802.

A low-cost paper-based blood urea nitrogen optical biosensor for renal surveillance in fingertip blood

In this study, we developed a low-cost, handheld optical biosensor for measuring blood urea nitrogen (BUN) levels in fingertip blood. This biosensor can connect to a cloud-enabled smartphone for remote monitoring of renal diseases. The biosensor features a simple, stackable and multilayer paper-based strip design, which not only achieves a linear optical fast response to BUN concentration but also reduces the complexity of the optical reader. Excellent detection performance was obtained via a unique photoelectric detection algorithm. The proportional function for calculating the analyte concentration was established using blood samples with different BUN concentrations, resulting in a wide detection range of 2.46–38.14 mM and a low detection limit of 0.03 mM. Clinical sample testing demonstrated the biosensor’s high reliability, showing strong agreement with the bulky biochemistry analyzer (gold standard), with a correlation coefficient R2 = 0.9635. It is also capable of connecting to a cloud-enabled smartphone via Bluetooth to transmit test data, which has an easy-to-use interface, thus enabling proactive health management or remote diagnosis. We believe that the proposed BUN biosensor can be a big boost to the daily monitoring of renal diseases and has promising prospects in contributing to the development of the IoMT.

XBP1 modulates endoplasmic reticulum and mitochondria crosstalk via regulating NLRP3 in renal ischemia/reperfusion injury

The functional status of mitochondria and the endoplasmic reticulum are central to renal ischemia/reperfusion injury (IRI). X-box binding protein 1 (XBP1) is an important transcription factor in endoplasmic reticulum stress. NLR family pyrin domain containing-3 (NLRP3) inflammatory bodies are closely related to renal IRI. In vivo and in vitro, we examined the molecular mechanisms and functions of XBP1-NLRP3 signaling in renal IRI, which influences ER-mitochondrial crosstalk. In this study, mice were subjected to 45 min of unilateral renal warm ischemia, the other kidney resected, and reperfusion was performed for 24 h in vivo. In vitro, murine renal tubular epithelial cells (TCMK-1) were exposed to hypoxia for 24 h and reoxygenation for 2 h. Tissue or cell damage was evaluated by measuring blood urea nitrogen and creatinine levels, histological staining, flow cytometry, terminal deoxynucleotidyl transferase-mediated nick-end labeling, diethylene glycol staining, and transmission electron microscopy (TEM). Western blotting, immunofluorescence staining, and ELISA were used to analyze protein expression. Whether XBP1 regulates the NLRP3 promoter was evaluated using a luciferase reporter assay. Kidney damage was reduced with decreasing blood urea nitrogen, creatinine, interleukin-1β, and interleukin-18 levels. XBP1 deficiency reduced tissue damage and cell apoptosis, protecting the mitochondria. Disruption of XBP1 was associated with reduced NLRP3 and cleaved caspase-1 levels and markedly improved survival. In vitro in TCMK-1 cells, XBP1 interference inhibited caspase-1-dependent mitochondrial damage and reduced the production of mitochondrial reactive oxygen species. The luciferase assay showed that spliced XBP1 isoforms enhanced the activity of the NLRP3 promoter. These findings reveal that XBP1 downregulation suppresses the expression of NLRP3, a potential regulator of endoplasmic reticulum mitochondrial crosstalk in nephritic injury and a potential therapeutic target in XBP1-mediated aseptic nephritis.

Forsythiaside A ameliorates sepsis-induced acute kidney injury via anti-inflammation and antiapoptotic effects by regulating endoplasmic reticulum stress

Ethnopharmacological relevanceSepsis is a systemic inflammatory response syndrome caused by an infection in the body, and accompanying acute kidney injury (AKI) is a common complication of sepsis. It is associated with increased mortality and morbidity. Forsythia Fructus, the dried fruit of Forsythia suspensa (Thunb.) Vahl, is a commonly used traditional Chinese medicine.Aims of the studyThis study aimed to elucidate the protective effect of Forsythiaside A (FTA) on sepsis-induced AKI by downregulating inflammatory and apoptotic responses, and exploring its underlying mechanism.MethodsSeptic AKI was induced through intraperitoneal injection of LPS (10 mg/kg) using male C57BL/6 mice and pretreated with FTA or control saline. First, we assessed the degree of renal injury by creatinine, blood urea nitrogen measurement, and HE staining of renal tissue; secondly, the inflammation and apoptosis were measured byELISA, qPCR, and TUNEL immunofluorescence; finally, the mechanism was explored by computer molecular docking and Western blot.ResultsOur data showed that FTA markedly attenuated pathological kidney injuries, alleviated the elevation of serum BUN and Creatinine, suggesting the renal protective effect of FTA. Notably, FTA significantly inhibited the renal expression of proinflammatory cytokine IL-1β, IL-6, and TNF-α both at protein and mRNA levels and attenuated cell apoptosis in the kidney, as measured by caspase-3 immunoblot and TUNEL assay, indicating its anti-Inflammation and antiapoptotic properties. Mechanistically, administration of LPS resulted in robust endoplasmic reticulum (ER) stress responses in the kidney, evidenced by glucose-regulated protein 78(GRP78) upregulation, protein kinase RNA–like endoplasmic reticulum kinase (PERK) activation, eukaryotic initiation factor 2 alpha (elF2α) phosphorylation and C/EBP homologous protein (CHOP) overexpression, which could be significantly blocked by FTA pretreatment. Dynamic simulation and molecular docking were performed to provide further insight.ConclusionsCollectively, our data suggest that FTA ameliorates sepsis-induced acute kidney injury via its anti-inflammation and antiapoptotic properties by regulating PERK signaling dependent ER stress responses.

Does Omeprazole, the Proton-Pump Inhibitor, Affects the Structure of the Kidney of Male Albino Rats? Histological and Laboratory Study.

This study was done to assess the injurious effects of omeprazole by an in vivo experimental study on rat kidneys. Forty-two adult male albino rats were divided into four groups: Control group (I) in which rats were not administrated any treatment. In Groups IIa, IIb, and IIc rats received daily oral omeprazole in dose of 0.75 mg per kg for 2, 4, and 6 weeks, respectively. At the end of the experiment, blood samples were collected for serum creatinine and blood urea nitrogen measurement. Then, animals were sacrificed, and kidney specimens were processed for paraffin blocks, sectioned and stained with H and E, Mallory trichrome and Periodic acid-Schiff, then examined by the light microscope. Stained sections and image analysis were used to count vacuolated cells, pyknotic nuclei, tubular casts, and area percent of collagen fiber deposition, and then, data were subjected to the statistical analysis. Examination of omeprazole-treated groups showed injury of renal corpuscles, renal tubules, and vascular congestion with inflammatory cell infiltrate in renal interstitium. Thickening of basement membrane with deposition of collagen fibers was also detected. Statistically significant increase in the number of vacuolated cells, pyknotic nuclei, hyaline casts, and area percentage of collagen fiber deposition as compared with the control group was noticed, with deterioration of renal function tests. It was concluded that the long-term use of omeprazole resulted in structural damage of rat renal tissue associated with deterioration of renal function in a time-dependent manner.

Evaluation of Novel Urinary Biomarkers in Beagle Dogs With Amphotericin B-Induced Kidney Injury.

Next-generation urinary protein biomarkers have been qualified to enable monitoring for drug-induced kidney injury in toxicology studies conducted in rats. However, there is limited literature on the utility of these biomarkers in dogs. To add to the existing body of knowledge on the utility of the next-generation drug-induced kidney injury (DIKI) biomarkers, we evaluated the value of these biomarkers for the early detection of DIKI in Beagle dogs using a differentiated nephrotoxicant, Amphotericin B (AmpB). In dogs with AmpB-induced kidney injury, we monitored the response of urinary albumin, total protein, clusterin, kidney injury molecule 1, neutrophil gelatinase-associated lipocalin and N-acetyl-beta-D-glucosaminidase. We also measured blood urea nitrogen, serum creatinine and cystatin C. The results showed that urinary clusterin (up to ∼ 112x) was much more sensitive to AmpB-induced kidney injury relative to other biomarkers. Moreover, other than urinary clusterin and to a much lesser extent urinary albumin and total protein, none of the other biomarkers analyzed in this study were more sensitive than blood urea nitrogen and serum creatinine. The AmpB related tubular alterations were characterized by minimal to mild, multifocal necrosis, degeneration, regeneration, dilatation and mineralization. The mild nature of these histopathologic findings further attested to the sensitivity of urinary clusterin to AmpB-induced kidney injury in dogs. These results will help drug developers make informed decisions when selecting urinary biomarkers for monitoring DIKI in dogs for toxicology studies.

Effect of gentamicin on renal function, oxidative stress, and some markers of antioxidants in male rats

Gentamicin overdose is a frequent cause of nephrotoxicity and possible death, so this study aimed to investigate the effect of gentamicin on serum renal enzyme, oxidative stress, and some markers of antioxidants in male rats. Methods: A total of 20 rats (3 to 6 months old) raised at high ambient temperature were divided into two equal groups, 10 rats each. The first control group was administered normal saline and the second group of rats was treated with gentamycin (80 mg/kg body weight by intraperitoneal injection) for 30 days. Blood samples were drawn to measure blood urea nitrogen (BUN) levels, serum creatinine, total protein, glutathione (GSH), Malondialdehyde (MDA), and catalase (CAT) levels, and activities were evaluated. Results: In the gentamicin-treated group, significant increases in blood urea nitrogen activities, serum creatinine, total protein activities, malondialdehyde (MDA) levels, and a significant decrease in catalase (CAT) and glutathione activities were determined compared to the control group. Conclusion: Administration of gentamycin produces notable biochemical changes in a dose-dependent manner associated with increased renal enzyme, markers of oxidative stress, and decreased antioxidant activity.

Long non-coding RNA TUG1 knockdown promotes autophagy and improves acute renal injury in ischemia-reperfusion-treated rats by binding to microRNA-29 to silence PTEN

ObjectiveLong noncoding RNA (lncRNA) taurine upregulated gene 1 (TUG1) is increased under the condition of ischemia. This study intended to identify the mechanism of TUG1 in renal ischemia-reperfusion (I/R).MethodsFirst, a rat model of acute renal injury induced by I/R was established, followed by the measurement of blood urea nitrogen (BUN), serum creatine (SCr), methylenedioxyphetamine (MDA) and superoxide dismutase (SOD) in the serum of rats. TUG1 was knocked down in I/R rats (ko-TUG1 group). Next, histological staining was used to evaluate the pathological damage and apoptosis of rat kidney. Western blot analysis was used to detect the levels of apoptosis- and autophagy-related proteins and transmission electron microscope was used to observe autophagosomes. Autophagy and apoptosis were evaluated after inhibition of the autophagy pathway using the inhibitor 3-MA. The targeting relation among TUG1, microRNA (miR)-29 and phosphatase and tensin homolog (PTEN) were validated. Lastly, the effects of TUG1 on biological behaviors of renal tubular cells were evaluated in vitro.ResultsIn vivo, the levels of BUN, SCr and MDA in the serum of I/R-treated rats were increased while SOD level and autophagosomes were reduced, tubule epithelial cells were necrotic, and TUG1 was upregulated in renal tissues of I/R-treated rats, which were all reversed in rats in the ko-TUG1 group. Autophagy inhibition (ko-TUG1 + 3-MA group) averted the protective effect of TUG1 knockdown on I/R-treated rats. TUG1 could competitively bind to miR-29 to promote PTEN expression. In vitro, silencing TUG1 (sh-TUG1 group) promoted viability and autophagy of renal tubular cells and inhibited apoptosis.ConclusionsLncRNA TUG can promote PTEN expression by competitively binding to miR-29 to promote autophagy and inhibited apoptosis, thus aggravating acute renal injury in I/R-treated rats.

COMPARISON OF BLOOD SYMMETRIC DIMETHYLARGININE AND CREATININE AS ENDOGENOUS MARKERS OF KIDNEY FUNCTION IN CAPTIVE TIGERS (PANTHERA TIGRIS).

Chronic kidney disease (CKD) is a common cause of morbidity and mortality in captive tigers (Panthera tigris). Blood creatinine (Cr) and blood urea nitrogen measurements are inexpensive and common biomarkers used to evaluate renal function. However, several limitations have been reported regarding their sensitivity and interindividual variability. Symmetric dimethylarginine (SDMA) has been suggested to be a more sensitive biomarker that is less affected by extrarenal factors and has a strong correlation with glomerular filtration rate and blood Cr in several species. This project aimed to identify the usefulness of SDMA as an endogenous marker of kidney function in captive tigers. The hypothesis of this study is that increased circulating SDMA is positively associated with increased blood Cr. SDMA and Cr were measured in 65 banked samples (serum and plasma) from 30 individual captive tigers. The samples were collected over a 38-y period and stored at -21°C. SDMA and Cr concentrations were determined using the commercially available SDMA test and enzymatic colorimetric methods, respectively. SDMA had a significant positive association with Cr (for every 1 unit increase of log SDMA, Cr increased by 82%, P = 0.0002). Age and subspecies influenced Cr but not SDMA concentrations. In one animal, blood SDMA increased above the ZIMS reported range. approximately 3.6 mo before Cr increased. SDMA is currently indicated for the diagnosis of CKD in domestic felids and seems also promising in nondomestic felids. Further prospective studies might improve the understanding of the performance of this biomarker.

MO342ADMINISTRATION OF ASTRAGALUS MEMBRANACEUS PREVENTED CISPLATIN-INDUCED AKI, ESPECIALLY IN OLD MICE

Abstract Background and Aims Recent findings suggest that acute kidney injury (AKI), which occurs frequently but is believed to be completely reversible, is an important factor driving chronic kidney disease (CKD) pathogenesis or progression. We have investigated Astragalus membranaceus (AM), which has been shown to have various pharmacological effects on several organs (see http://nccih.nih.gov/health/astragalus). However, up to now, little evidence of its effectiveness against CKD has been provided. We hypothesized that AM could target AKI and that sustainable prevention of AKI by AM might delay pathogenesis and progression of CKD. Here we focused on AKI as a promoter of CKD progression in order to examine the effects of AM histologically and histochemically in mice. Method Here we used two groups of female C57BL/6 mice: one that was aged 12 weeks and one that was aged 52 weeks. After the first blood collection (of approximately 0.2 ml), the two age groups of mice were administered AM powder mixed with sterilized 0.5% methylcellulose 400 (w/v) (the AM-administered group) or sterilized 0.5% methylcellulose 400 (the control group), respectively. Two hours after the administration, 0.5 mg/ml cisplatin (20 mg/kg or 14 mg/kg) or 0.9% NaCl were injected intraperitoneally. Three days after injection, blood was collected and kidneys were harvested. We measured blood urea nitrogen (BUN) and creatinine (CRE) to detect AKI, and assessed histological change in dissected kidney sections stained with Hematoxylin-Eosin and Periodic acid-Schiff and histochemical change in sections stained with anti-CD3 and anti-CD68 antibodies. Generally, 20 mg/kg cisplatin was used to induce AKI in the experimental model. Results Injection with 20 mg/kg cisplatin was shown to induce AKI pathology in young mice and shorten survival in old mice, and AM administration was unable to improve AKI pathology in young mice or survival in old mice. Next, we injected mice in both age groups with 14 mg/kg cisplatin. We found that this dose significantly increased serum BUN or CRE and caused histological damage in renal tubule epithelial cells and glomeruli in old mice but not in young mice, which showed no pathological change. And Astragalus treatment in advance almost totally prevented these pathological changes in old mice. The AKI generated in old mice with 14 mg/kg of cisplatin was significantly normalized by pretreatment with AM. Next, histochemical analysis of renal CD3- and CD68-positive cells revealed both were increased in the murine AKI model induced by injection with 20 mg/kg cisplatin. Interestingly, in old mice, 14 mg/kg cisplatin-AKI increased CD3-positive cells but not CD68-positive cells. These findings suggest that AM may improve daily minor disturbances, such as AKI, that cause pathogenesis and progression of CKD especially in old age. Conclusion AM administration, at least in part, can reduce day-to-day AKI occurrence, but is ineffective in young kidneys. However, sustained use of AM could play a critical role in prolonging the activity of aged kidneys. Acknowledgments We thank the Education and Research Support Center, Tokai University, for technical assistance. This work was supported by a grant from the Japan Society for Promotion of Science JSPS KAKENHI KIBAN-C (Grant Number 16K09259) and by Tokai university general research organization grant.

Blood urea nitrogen to albumin ratio is a predictor of in-hospital mortality in older emergency department patients

In this study, we aimed to evaluate the first measured blood urea nitrogen (BUN)/albumin ratio in the emergency department (ED) as a predictor of in-hospital mortality in older ED patients. This retrospective observational study was conducted at a university hospital ED. Consecutive patients aged 65 and over who visited the ED in a three-month period were included in the study. The BUN, albumin, creatinine, and estimated glomerular filtration rate (eGFR) of patients were recorded. The primary end point of the study was in-hospital mortality. A total of 1253 patients were included in the statistical analyses of the study. Non-survivors had increased BUN levels (32.9 (23.3-55.4) vs. 20.2 (15.4-28.3) mg/dL, p<0.001), decreased albumin levels (3.27 (2.74-3.75) vs. 3.96 (3.52-4.25) g/dL, p<0.001), and increased BUN/albumin ratios (10.19 (6.56-18.94) vs. 5.21 (3.88-7.72) mg/g, p<0.001) compared to survivors. An increased BUN/albumin ratio was a powerful predictor of in-hospital mortality with an area under the curve of 0.793 (95% CI: 0.753-0.833). Malignancy (OR: 2.39; 95% CI: 1.59-3.74, p<0.001), albumin level<3.5g/dL (OR: 2.75; 95% CI: 1.74-4.36, p<0.001), and BUN/albumin ratio>6.25 (OR: 2.82; 95% CI: 1.22-6.50, p<0.015) were found to be independent predictors of in-hospital mortality in older ED patients. According to our findings, older patients with a BUN level>23mg/dL, an albumin level<3.5g/dL, and a BUN/albumin ratio>6.25mg/g in the ED have a higher risk of in-hospital mortality. Additionally, the BUN/albumin ratio is a more powerful independent predictor of in-hospital mortality than the BUN level, albumin level, creatinine level, and eGFR in older ED patients.

Healthy adult vegetarians have better renal function than matched omnivores: a cross-sectional study in China

BackgroundAn appropriate diet is an important determinant of kidney health. However, the association between vegetarian diets and renal function is unclear. We aimed to study the association between vegetarian diets and renal function in healthy adults.MethodsA total of 269 vegetarians and 269 sex- and age-matched nonvegetarian omnivores were enrolled in this cross-sectional study. Basic characteristics and daily dietary intakes were assessed by face-to-face interviews. Blood samples were collected, and renal function was assessed by measuring blood urea nitrogen (BUN), serum creatinine (SCr), uric acid (UA) and the estimated glomerular filtration rate (eGFR). Blood pressure, fasting blood glucose and blood lipid profiles were also assessed.ResultsThe average age of the vegetarians was 35.4 ± 8.6 years, 82.2% of whom were female. We evaluated the association between vegetarian diets and renal function using multivariate analysis. Compared with omnivores, vegetarians had lower BUN [β = − 0.63, 95% confidence interval (CI): (− 0.88, − 0.38)], SCr [β = − 2.04, 95% CI:(− 4.10, 0.02)], and UA levels [β = − 15.15, 95% CI: (− 27.81, − 2.50)] and higher eGFRs [β = 4.04, 95% CI: (0.30, 7.78)] after adjusting for sex, age, body mass index (BMI), physical activity, alcohol consumption, smoking status, low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), systolic pressure and fasting blood glucose. Further analysis of food composition and renal function showed that dietary fiber intake was significantly negatively associated with BUN [β = − 0.02, 95% CI: (− 0.03, 0.00)], SCr [β = − 0.14, 95% CI: (− 0.25, 0.04)], and UA levels [β = − 0.72, 95% CI: (− 1.36, 0.07)] and positively associated with the eGFR [β = 0.20, 95% CI: (0.00, 0.40)].ConclusionsHealthy adult vegetarians have better renal function than omnivores, and the higher dietary fiber intake associated with vegetarian diets may contribute to the protective effect on renal function.

P0529THE DIFFERENCE IN DIETARY RESTRICTION-INDUCED NEPHROPROTECTIVE MECHANISMS IN YOUNG AND OLD ANIMALS

Abstract Background and Aims Acute kidney injury (AKI) is a widespread disease affecting mostly old people. Dietary restriction (DR), based on the reduction of food intake, is believed to be one of the most efficient approaches ameliorating damage in different pathological conditions including age-associated diseases. The aim of the study was to investigate the protective mechanisms of DR in the model of AKI in young and old rats. Method All experiments were made on young (3-4 months) and old (22-24 months) male rats. DR was performed by limiting the amount of food for 35% of the ad libitum (AL) daily intake. Since earlier, we showed ineffectiveness of 4-weeks DR in old rats, in this study we applied 35% DR lasting 8 weeks for old rats and 4 weeks for young rats. During DR, we registered the weight loss and measured the level of adiponectin, as this hormone is closely associated with adipose tissue metabolism. Renal ischemia/reperfusion (I/R) was used as a model of ischemic AKI. I/R was performed by clamping the left renal pedicle for 40 minutes followed by reperfusion with simultaneous contralateral nephrectomy. The severity of AKI was evaluated by measuring blood urea nitrogen (BUN), serum creatinine (SCr) and the levels of protein biomarkers of AKI (NGAL and L-FABP) in urine. Proliferation in kidney epithelium in response to I/R was analyzed by PCNA protein level in kidney tissue. We evaluated the function of mitochondria by measuring TMRE/MitoTracker Green ratio in vital kidney slices; in kidney homogenates, we also analyzed levels of Bcl-XL and Bcl-XS proteins. The production of reactive oxygen species (ROS) was evaluated by staining vital kidney slices with DCF. The content of lipid peroxidation products was measured using Image-iT Lipid Peroxidation Kit, and the level of carbonylated proteins was determined by OxyBlot Protein Oxidation Detection Kit. The activation of autophagic-lysosomal system was estimated by western blotting to LC3 II/LC3 I ratio and LAMP1 level, as well as by staining vital kidney slices with LysoTracker Green probe. Results The body weight of rats during DR dropped as far as 20% by the end of 4 weeks in young rats and 30% by the end of 8 weeks in old rats. Nevertheless, adiponectin concentration elevated during DR only in the serum of young rats. DR strongly influenced mitochondria function, in particular, elevated mitochondrial membrane potential both in kidney cells of young and old rats. DR also resulted in increasing the Bcl-XL level. We revealed the decrease of ROS and lipid peroxidation products in vital kidney slices, but only in kidneys of young rats. However, DR reduced the content of carbonyl groups more than 2 times in animals of both ages. We showed that activation of autophagy in response to DR and I/R occurred only in the kidneys of young rats, indicating deterioration of autophagy signaling in old animals. We also found that 48 h after I/R PCNA level increased 19 times in young kidney, although old rats showed only 4-fold elevation of kidney cells proliferation. Estimation of kidney injury markers (NGAL, L-FABP) in urine revealed that 2-month DR led to some protection in old rats. Nonetheless, despite all positive alterations in kidney tissue of old rats, DR was not able to ameliorate impairment of kidney function after I/R, whereas all young rats showed significant improvement of SCr and BUN levels. Conclusion Short-term DR has a significant nephroprotective effect against renal I/R in young rats. Old animals require longer periods of food restriction, after which some protective alterations are observed. We propose, protection of kidney in old and young rats is implemented through slightly different mechanisms and some of them are missing in old animals.

Rapid Evaluation Method of Post Dialysate Urea Nitrogen Measurement for Chronic Kidney Disease Patients By Using Non-Enzymatic N-Doped Carbon Supported Nickel Based Biosensor

An effective hemodialysis is essential for patients with chronic kidney diseases to maintain their kidney’s functionalities and health conditions. Not only the treatment usually takes 3-4 times a week, but a monthly measurement of blood urea nitrogen (BUN) is also a time-consuming requirement process, which in turn, provides a rough estimation of blood quality with respect to blood life cycle. However, a lack of feedback for each treatment’s efficacy still remains a major challenge for prognostic hemodialysis. Consequently, self-precaution or spontaneous adjustment on patients’ dietary can be difficult to achieve with little predicted quantitative information. Herein, we present a rapid evaluation method for the first time to quantify dialysate urea nitrogen (DUN), considering as a body waste information after hemodialysis treatment with our proposed model of estimation. Our systematic design on sample preparation with optimized supporting electrolyte enables a suitable linear range from 1 to 5 mM to predict urea concentration in patients’ post-treatment dialysate solution on a scalable non-enzymatic N-doped Carbon (NC) supported nickel (Ni) catalyst. Mechanistically, Ni in alkaline medium can form hydroxyl layers, especially Ni(I/II) redox couple to bind with urea molecules. Although this commonly known process is often exploited in many electrochemical reactions, the strong alkaline electrolyte often diminishes a weak target output, particularlly in sensing applications, thereby requiring secondary layers such as organic or macromolecular polymers to capture the target molecules. In this work, we optimize the alkaline medium and dialysate volume ratio and include three important factors: (i) reference dialysate sensitivity (mref), (ii), roughness (Rf), and (iii) capacitive current (Ic), respectively, into our predicted model. Each factor is also experimentally carried out. In detail, mref is -1660.40 A.mol-1cm, obtained from a current density and urea concentration calibration plot by using differential pulse voltammetry (DPV) on Ni/NC in our simulated reference dialysate solution with successive addition of urea concentration from 1-5 mM on 900 rpm rotating disk electrode. In addition, Rf is estimated to be 2.56 from electrochemical surface area (ECSA) in Randles-Sevcik equation, that is calculated by anodic peaks of 10 mM ferricyanide redox couple in 1 M potassium chloride supporting electrolyte. Furthermore, Ic is calculated to be the capacitive current density of 1.57 mA.cm-2, based on Gouy-Chapman double layer at the same scan rate of DPV (0.05 V/s) and the roughness of Ni, assessed by cyclic voltammetry from -0.35 to -0.05 V versus Ag/AgCl in 0.5 M potassium hydroxide. As shown in Figure 1, our proposed model is illustrated in equation (1) with parameter described in Table below. For further validation, we estimate urea concentrations in post-treatment dialysate, obtained from three patients by DPV on Ni/NC biosensor for 5 independent trials in comparison with their clinical standard results. It was found that percentage of relative error between our predicted urea concentrations and the clinical results in real samples are those of 1.30 %, 0.25 %, and 0.52 % for patient I-III, respectively, providing a highly accurate and rapid assessment for this important indicator in hemodialysis. Based on our observation, DUN evaluation has an inversely proportional relationship with the difference of BUN values between before and after hemodialysis: 48.3, 41.2, and 53.2 mg.dL-1 for patient I-III, accordingly. With enzyme-free, scalable, and economical choice of sensing design, this finding can become appreciable to further develop as an on-site monitoring prognostic tool and provide instantaneous feedback on treatment’s efficacy and daily dietary management of chronic kidney disease patients. Figure 1

Opuntia ficus indica Fruits Ameliorate Cisplatin-Induced Nephrotoxicity in Mice.

This study aims to determine the potential renal protective effects of Opuntia ficus-indica (L.) Miller (OFI) fruits against cisplatin-induced nephrotoxicity in mice. The antioxidant activity of OFI methanol extract was calculated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid (ABTS) free radical scavenging assays. Furthermore, the LC-mass spectroscopy (MS) analysis of the OFI fruit extract was carried out. Mice were treated with OFI extract (250 mg/kg) for 10 d and injected with a single dose of cisplatin (20 mg/kg) on the 7th day. The blood samples were collected to measure blood urea nitrogen (BUN) and serum creatinine level on the 10th day. Their kidneys were removed for histopathological examination. The renal morphological alterations were assessed through the mesangial matrix index and transmission electron microscopy (TEM). The OFI fruit extract showed significant in vitro antioxidant activity. In further, it was revealed that the cisplatin-induced nephrotoxicity in mice was ameliorated; this outcome was supported by both histological examination results and the depicted reduced levels of BUN and serum creatinine. The potent antioxidant compounds which were detected in the extract of OFI fruits such as myricetin, quercetin, luteolin might be responsible for the observed renoprotective effect. The results clarified that the OFI fruit extract could ameliorate cisplatin-induced renal toxicity in mice via including antioxidant and renoprotective compounds.